1. Theme 2: Abiotic Cycling and Scavenging
Grand Challenge – What controls scavenged TEI distributions and their role in biogeochemistry?
diversity of scavenging TEI rates and mechanisms
chemical speciation
dominant 'scavenging‘ colloids/particles
role of desorption/reversibility
particulate-dissolved exchange (aggregation)
nepheloid layer processes

2. T. Weber – Scavenging Inverse Modeling
With how much sophistication should inverse models represent scavenging?
Does GEOTRACES allow is to estimate TEI settling rates more generally?
Can we quantify the settling rate and driving processes governing sinking? (e.g. adsorption/ desorption aggregation/ disaggregation, uptake/ egestion)?

3. P. Lam – Particulate Speciation
Are mineral-specific Kd values ubiquitously applicable across ocean and coastal environments?
Is particle surface area the truly controlling variable?
Can we model/predict the distribution of particle types and concentrations through multiple elemental biogeochemistry?

4. K. Buck – Dissolved Speciation and Ligands
How should we describe the creation and destruction processes and composition of strong and weak ligands in the surface and deep ocean?
Are siderophores the main story?
What is the lifetime of the ligands and does patchiness suggest it is short?

5. Anderson – Systematics and Surprises
Is all scavenging reversible?
How important is oxyhydroxide precipitation, and is it irreversible?
What drives the minimum in tracer concentrations in the deep Chl maximum?
What controls preformed TEI values in source waters?